Separation of ferrous chloride from material containing metallic nickel



Patented May 4, 1954 SEPARATION OF FERROUS CHLORIDE FROM MATERIAL GONTAINING METAL- LIC NICKEL Marion Ernest Graham, Parma, and Edward A. Beidler, Columbus, Ohio, assignors, by mesne assignments, to Republic Steel Corporation, Cleveland, Ohio, a corporation of New Jersey No Drawing. Application May 8, 1950,

Serial No. 160,822

4 Claims. 1

This present invention relates to a process for the separation of ferrous chloride from material containing metallic nickel. One embodiment of this invention is as a particular step in a larger process for treating ores containing iron and nickel values to obtain those values separately in some useful forms.

One of the early phases of such an overall process could be the step of chloridizing the original ore material, a step which forms no part of the present invention. If such a chloridizing step be carried out under conditions such that the iron values are selectively chloridized, while the nickel values are reduced to metallic nickel, there will be produced a material containing F6012, metallic nickel usually in finely divided form, gangue, and possibly, in addition, some reduced metallic iron. It is such a mixture that is contemplated as the starting material on which the process of the present invention may be used. It will be understood, of course, that such a material may be the result of other processes, and that the method of producing the aforesaid mixture forms no essential part of this invention.

It is known that ferrous chloride can be vaporized and thereby separated from inert materials under suitable temperature conditions. However, We have found that when metallic nickel is present mixed with ferrous chloride,

a back reaction tends to take place between some of the metallic nickel and ferrous chloride present to form metallic iron and nickel chloride. This reaction may be represented by the equation FeCl2+Ni:NiClz+Fe. It will be seen that the occurrence of such reaction is undesirable for several reasons: first, the sublimed material .will not consist of substantially pure ferrous chloride as desired, but will be contaminated with nickel chloride; and second, at least some of the nickel, which may be desired to be recovered in the metallic state, is converted to a volatile chloride and lost or mixed with ferrous chloride.

A general object of the present invention is, therefore, to provide a method of separating ferrous chloride from the remaining materials in the form of substantially pure ferrous chloride free from nickel chloride.

It is a further object to maintain the metallic nickel in the starting material in metallic form without losing any of it as volatile nickel chloride.

Summarizing the present invention, the separation of substantially pure ferrous chloride is accomplished by providing in the starting material an amount of metallic iron sufficient to assure that such iron will be present in the ratio of at least about one part of metallic iron to nine parts of metallic nickel by weight. The metallic iron may be all or in part present in the original mixture or it may be entirely added. The term providing metallic iron or equivalent language as used in the claims includes either a starting material which has such metallic iron present initially or a starting material which did not initially contain metallic iron, but to which metallic iron has been added. The material, which now includes ferrous chloride, metallic nickel, metallic iron and possibly some inert or gangue materials is then heated to a temperature in the range of about 600 C. to about 1025 C. for a time sufficient to vaporize all the FeClz present. The vaporized FBC12 may be removed from the non-volatile material by a sweep gas. As it has been found that the equation given above, as illustrating a reaction which is to be prevented in accordance with the present invention, is a reversible one which tends to reach an intermediate equilibrium condition, the present invention provides conditions assuring the desired results. Thils, by providing a quantity of finely divided metallic iron in the material as aforesaid there is assured either of the following results: (a) That the equation above will not operate in the directicn shown to produce any NiClz, or (b) if any NlClz if formed, then this NiClz will immediately react with metallic iron, present as aforesaid, to produce metallic nickel and FeCl;;. The net result is that substantially all the metallic nickel initially present remains as such in the residue after all the FeClz initially present has been distilled therefrom.

The present application is one of a group of seven co-pending applications, all the inventions of the same inventors, four of these cases relating to nickel and reactions involving nickel and the other three relating to cobalt and reactions involving cobalt. The cases may be compared and distinguished as follows:

(a) Ser. No. 160,821, filed May 8, 1950 relates to treating a starting material in the non-gaseous (liquid and/or solid) form and consisting essentially of NlClz and Feclz, and wherein there is more FeClz than NiClz. This starting material is treated in a reaction or sublimation zone, in the presence of a certain amount of metallic iron, to produce a final product which is vaporized FeClz, removed from the sublimation zone as such, leaving only metallic iron and metallic nickel in the sublimation zone.

(b) Serial No. 210,433, filed February 10, 1951, relates to treating a starting material, essentially the same as Ser. No. 160,821, except that in this instance the starting material is introduced into the reaction zone in a solely gaseous state. The reaction and the final products are substantially the same as in Ser. No. 160,821.

Ser. No. 160,822, filed May 8, 1950 (the present application) relates to the preventing or minimizing of a possibleback reaction. The starting material consists essentially of ferrous chloride and metallic nickel. It is desired to separate these materials without permitting, or at least minimizing, a possible back reaction therebetween which would produce nickel chloride and metallic iron. To do this, the starting material is introduced into a reaction or sublimation zone in which metallic iron is present. The starting material as introduced into this zone is in a non-gaseous state. The final products are substantially pure ferrous chloride vapor, which is removed from the zone as such, and metallic nickel and metallic iron which remain in the zone.

(d) Ser. No. 294,058, filed June 17, 1952, discloses a process for treating a starting material substantially the same as in Ser. No. 160,821. This case has been amended so as to preclude the claims reading upon separation of the prodnets of the reaction by vaporization as in Ser. No. 160,821; but in this case the separation following the reaction is eifected by withdrawing the metallic nickel produced (by a reaction the same as in Ser. No. 160,821) by withdrawing massive pieces of iron, to which the deposited nickel adheres physically, from the fused bath of the starting materials. Neither the ferrous chloride nor any nickel chloride present is intentionally volatilized. This application is junior to application Ser. No. 160,821, so that the only subject matter claimable therein is subject matter which cannot be supported by the disclosure of Ser. No. 160,821; all the common subject matter being claimed in Ser. No. 160,821.

(6) Ser. No. 291,816, filed June a, 1952, is the first of the three cobalt applications and is the cobalt counterpart of the nickel case, Ser. No. 160,821, distinguishing therefrom by being directed to cobalt and its chloride, rather than nickel and its respective chloride. This case is further distinguished in the degree of purity of the sublimate.

(1) Ser. No. 320,835, filed November 15,1952, is the cobalt counterpart of nickel case, Ser. No. 210,433. It distinguishes from cobalt case Ser. No. 291,816 in the same way discussed above as to the respectively corresponding nickel cases, while distinguishing from its corresponding nickel case, Ser. No. 210,433, by the difference between cobalt and nickel.

(9) Ser. No. 321,514, filed November 19, 1952, is the cobalt case corresponding to the nickel case Ser. No. 160,822. It distinguishes from the other cobalt cases as discussed above in respect to the respectively corresponding nickel cases, while distinguishing from its nickel counterpart, Ser. No. 160,822, by the differences between nickel and cobalt.

Thus, in accordance with the present invention, it is necessary to have present metallic iron to react with any nickel chloride which might be formed from a reaction between the metallic 4 nickel and the ferrous chloride originally present. We have found that when using a weight ratio of iron to nickel in the order of 1 to 9, the amount of nickel chloride which is formed and carried over in the sublimate is reduced to a practicable minimum. We have further found that if the iron is present in a ratio of about one part by weight to about three parts by weight of nickel, the sublimate, obtained from heating such a material to a temperature were FeClz has a substantial vapor pressure, will be substantially pure FeClz, substantially uncontaminated by any detectable amount of nickel chloride or by nickel in any form. It is our conclusion that when a 1:3 ratio of iron to nickel is used, such sublimate is substantially free of nickel chloride. An amount of iron in excess of the amount needed to produce a l to 3 weight ratio in respect to nickel is not particularly harmful, in that the process of the present invention is fully operative using such greater amounts.

As has been indicated above, the metallic iron which serves to inhibit the formation and/or separation by distillation from the mass of volatile nickel chloride and thereby to prevent the loss of nickel in this volatile form, may be initially present in the material in sufficient quantity to produce this effect, or it may be wholly or partially added.

In view of the fact that a chemical reaction, including the metallic iron, may be called for in accordance with the present invention, as aforesaid, it is desired to have the iron present in a readily available form. For this reason the iron is preferably present and/or introduced in a finely divided form and is well mixed with the other solid ingredients of the starting material. The fineness of the iron or the completeness of mixing are, however, not particularly critical.

We have found that the process of the present invention is substantially independent of the amount or proportion of FeClz present in the starting mixture, which is amply demonstrated by actual examples of the present process hereinafter given.

In practicing the present invention it is necessary to produce ferrous chloride vapor, so that the material being treated must be held in a temperature range sufficiently high to insure that the ferrous chloride will have a sufiicient vapor pressure. The low limit of such a temperature range may be conveniently placed at about 600 C., at which temperature Feclz has a substantial vapor pressure. It has been found, in practice, that at temperatures below 600 C., the rate of vaporization of FeCl is so slow as to make the process impracticable. The upper limit of the temperature range is fixed by the boiling point of ferrous chloride, which at atmospheric pressure is about 1025 C. In view of the fact that thevolatilization of the ferrous chloride is an endothermic process, the temperature of the mass from which the FeClz is vaporized cannot exceed this boiling point as long as any substantial amount of ferrous chloride remains therein. However, it will be understood that in cases where the materials are maintained at super-atmospheric pressures, the boiling point of ferrous chloride will be higher, so that correspondingly higher temperature limits can be employed. Therefore, the upper limit of the temperature range may be such as the boiling point of ferrous chloride at whatever pressure is being employed.

In general, it may be said that while the temperature is not particularly critical, the rate of removal of the ferrous chloride from the material present is, of course, a function of the temperature, so that the process is completely operative throughout a large temperature range as stated, the rate differing with different temperatures. The removal of vaporized ferrous chloride from the system may be effected either by operating at the boiling point of the ferrous chloride or by using a sweep gas in a manner similar to a steam distillation. Such a sweep gas is preferably an inert gas such as nitrogen.

It is contemplated that the process of the present invention may be carried on either as a batch or as a continuous type operation, suitable or conventional apparatus per se forming no part of the present invention, being used in either case. The pure FeClz vapor which is a result of this process may be condensed to solid or liquid form by any suitable cooling means, and may be used for any desired purpose. Alternatively, the vapor may be maintained at its high temperature and used for any purpose to which FeCla vapor is adapted. The residual material will contain metallic iron and metallic nickel. These metals may be separated from the gangue by any suitable method, magnetic or otherwise and/or melted together to form an alloy. The following examples illustrate the present process:

Example 1.-To illustrate the extent to which metallic nickel and ferrous chloride react to produce volatile NiClz, a mixture, consisting of 91% by weight of FGClz and the remainder nickel powder having been thoroughly mixed together and containing no metallic iron was heated in a nitrogen stream to a temperature of about soc C. and held at that temperature for one hour. A sublimate was obtained which contained 0.69% nickel by weight in the form of NiClz and the remainder FeClz. About 7% of the metallic nickel originally present went over to the sub limate during the test period in which 67.2% of the FeCl2 was transferred to the sublimate by the operation. This represented a very substantial loss of nickel in the form of volatile chloride which latter contaminated the ferrous chloride.

Example 2.When a mixture containing 90% FeClz, 9% nickel and 1% finely divided metallic iron was treated in the same way, the sublimate obtained was found to contain only 0.17% nickel by weight in the form of nickel chloride or about one-fourth as much as was present in the sublimate obtained from a mixture of Example 1.

This amount of nickel is not an undesired amount from the point of view of many uses to which FeClz may be put. It also is not excessive considered from the point of view of loss of metallic nickel.

Example -3.--A charge consisting of 96% FeClz, 1% finely divided iron and 3% metallic nickel, all by weight, was heated in a stream of nitrogen for one hour at about 800 C. as described above and the collected sublimate was found to consist of pure FeClz uncontaminated by any detectable amount of nickel chloride.

Example 4.A charge consisting of 52% R3012, 12% iron and 36% nickel was treated in the same manner as described in the Examples 2 and 3 above and again a collected sublimate wa found to consist of pure FeClz uncontaminated by nickel chloride.

Example 5.A charge consisting of 24% FeClz, 19% metallic iron and 57% metallic nickel was treated in the manner described above and again the sublimate consisted of pur ferrous chloride uncontaminated by any detectable amount of nickel chloride.

These latter three examples clearly illustrate that the process is equally operative in effecting a complete separation of FeClz uncontaminated by any substantial amount of nickel chloride irrespective of the amount or proportion of FeClz present in the starting material.

Thus while a separation of FeCh uncontaminated by any substantial amount of nickel chloride may be obtained by providing an iron to nickel weight ratio of at least about 1:3, a commercially practicable separation may be obtained using a similar weight ratio of 1:9.

While we have described our process in general, and have set forth in some detail the chemical and physical requirements thereof, it is recognized that the process may be operated by the substitution of such equivalents as will suggest themselves to those skilled in the art from the foregoing disclosure. We do not wish to be limited, therefore, except by the scope of the append ed claims, which are to be construed validly as broadly as the state of the art permits.

What is claimed is:

l. The process of separating ferrous chloride from a starting material consisting essentially of Feclz and metallic nickel, while substantially preventing loss of nickel in the form of NiClz, which comprises providing in contact with said material in a sublimation zone sufiicient metallic iron to assure that such iron is present in a ratio of at least about one part of such metallic iron to nine parts of metallic nickel by weight, maintaining said material in said zone including said metallic iron within the temperature range of about 600 C. to about the boiling point of FeCh at the ambient pressure, vaporizing all the FeClv. present, and separating the volatilized FeClz containing not more than about 0.17% of nickel in the form of nickel chloride from the remainder of said material by passing the volatilized FeClz from said zone to leave solely metallic iron and nickel in said zone.

2. The process according to claim 1, wherein said metallic iron is present in a weight ratio to metallic nickel of at least about 1:3, the FeCla vapor so separated containing less than a detectable amount of NiClz.

8. The process according to claim 1, wherein the weight ratio of said metallic iron to said metallic nickel is at least about 1:3, wherein the temperature in said zone is maintained in the range of about 600 C. up to but less than the boiling point of FeClz at the ambient pressure in said zone, and wherein the removal of FeClz vapor from said zone is assisted by passing a stream of inert gas through said zone, the F6012 vapor so separated containing less than a detectable amount of NiClz.

4. The process according to claim 1, wherein said metallic iron in said zone is in a finely divided form.

References Cited in the file of this patent UNITED STATES PATENTS Name Date Kroll et al Nov. 2, 1948 OTHER REFERENCES Number 

1. THE PROCESS OF SEPARATING FERROUS CHLORIDE FROM A STARTING MATERIAL CONSISTING ESSENTIALLY OF FECL2 AND METALLIC NICKEL, WHILE SUBSTANTIALLY PREVENTING LOSS OF NICKEL IN THE FORM OF NICL2, WHICH COMPRISES PROVIDING IN CONTACT WITH SAID MATERIAL IN A SUBLIMATION ZONE SUFFICIENT METALLIC IRON TO ASSURE THAT SUCH IRON IS PRESENT IN A RATIO OF AT LEAST ABOUT ONE PART OF SUCH METALLIC IRON TO NINE PARTS OF METALLIC NICKEL BY WEIGHT, MAINTAINING SAID MATERIAL IN SAID ZONE INCLUDING SAID METALLIC IRON WITHIN THE TEMPERATURE RANGE OF ABOUT 600* C. TO ABOUT THE BOILING POINTOF FECL2 AT THE AMBIENT PRESSURE, VAPORIZING ALL THE FECL2 PRESENT, AND SEPARATING THE VOLATILIZED FECL2 CONTAINING NOT MORE THAN ABOUT 0.17% OF NICKEL IN THE FORM OF NICKEL CHLORIDE FROM THE REMAINDER OF SAID MATERIAL BY PASSING THE VOLATILIZED FECL2 FROM SAID ZONE TO LEAVE SOLELY METALLIC IRON AND NICKEL IN SAID ZONE. 